Abstract

We studied the effect of post-deposition thermal annealing in the preparation of PbSquantum dot(QD)solar cells. We find an optimal annealing temperature that improves the power conversion efficiency by a factor of 1.5 for different sized QDs with bandgaps of 1.65 and 1.27 eV. We examined the onset of the photocurrent response and correlated that with domain grain growth and find that annealing the PbSQD array at 120 °C causes little change in the PbSQD size, bandgap, and open-circuit voltage and yet leads to an increase in the carrier transport as realized by an improved current response. We also find a decrease in the activation energy of a shallow trap, which also likely contributes to the improvement in the solar cell efficiency.

Received 21 November 2012Accepted 10 January 2013Published online 31 January 2013

Acknowledgments:

The authors thank B. Gregg for technical support on transition metal oxide deposition. We acknowledge support from the Center for Advanced Solar Photophysics, an Energy Frontier Research Center funded by the Office of Basic Energy Sciences, Office of Science, within Department of Energy. S.J. would like to thank NREL for hosting her Sabbatical visit and support from the Global Frontier R&D Program by the Center for Multiscale Energy Systems (NRF). DOE funding was provided by NREL through contract No. DE-AC36-08GO28308.

[Manufacture or treatment of devices consisting of
a plurality of solid state components or integrated circuits formed in or on a common
substrate or of specific parts thereof; Manufacture of integrated circuit devices or of
specific parts thereof, Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in or on a common substrate or of specific parts thereof; Manufacture of integrated circuit devices or of specific parts thereof, Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in or on a common substrate or of specific parts thereof; Manufacture of integrated circuit devices or of specific parts thereof]